Present telephone voice mail ("VM") systems provide users with voice mail accounts ("voice mailboxes"). Message senders may send telephone voice messages to recipients having voice mailboxes. The voice mailboxes allow the sender to store the voice messages intended for the recipient, on the recipient's VM system. The intended recipient may later replay the sender's message.
Message senders may be classified as local senders that have voice mailboxes on the recipient's VM system; remote senders that have a voice mailboxes on another VM system; or as remote senders that are otherwise connected to the public telephone network, but not connected to a VM system.
Present-day VM systems allow local senders to compose and send messages to other local recipients on the same VM system, while taking advantage of features provided by the VM system. For example, a sender may compose a message prior to sending. Similarly, a local sender may associate non-voice data with a message. This other data may include, for example, a message reply request; text data; sender identifying data; time of message data; and data to link other messages (attachments).
Remote senders that do not send messages from the recipient's VM system, typically cannot take advantage of all available VM system features. Some VM systems make a subset of the features available to callers calling the recipient's VM system through the public telephone network. Features of the VM system that do not require that a sender to have a voice mailbox are made available through a series of voice prompts. For example, an outside caller may call a recipient's VM system and compose a message before sending it to the recipient. Similarly, an outside caller may mark a composed message as urgent. Data is associated with such a message, allowing the VM system to indicate the message is urgent when it is replayed.
Other VM systems allow the transparent exchange of messages including messaging data and voice data between VM systems. Two or more physically separate VM systems of this type may be integrated. Remote users on each of the VM system may exchange messages across VM systems and take advantage of VM system features across the integrated systems. Messages destined for a remote recipient may be sent as if the recipient's voice mailbox were local to the senders' VM system. Messaging data required to implement features offered by the sender and recipient VM systems is exchanged between the VM systems along with voice data.
For example a sender having a voice mailbox on a first VM system composes and dispatches a message destined for a recipient on a second system. The sender associates a piece of data with the message indicating that the message is urgent. The sender may identify the recipient on the sender's VM system using an abbreviated identifier. Possibly, the abbreviated identifier appears as an extension. Some time later, after the sender has composed and dispatched the message, the first and second VM system establish a message exchange session. The sender's voice message is exchanged by first forming message data comprised of voice data and messaging data. These are sent from the first VM system to the second VM system during the exchange session. As well, other messages dispatched by other users on the first VM system are similarly exchanged during the session. The recipient's VM system receives the message data and, if possible, stores the voice data and any relevant associated messaging data in the recipient's mailbox. The recipient's VM system then treats the message like any other message originating on the recipient VM system. Thus, the recipient's system properly identifies associated data to advise the recipient that the message has been labelled as urgent. Other messaging data may similarly be exchanged. Moreover, messaging data generated in response to the receipt of a voice mail message may be sent back to the originating system during another exchange session.
Message data, including voice data and messaging data, may be exchanged between VM systems using a standardized protocol. One such protocol, known as the AMIS-Analog protocol ("AMIS-A") is supported by numerous VM system vendors and is described in the "Audio Messaging Interchanging Specification (AMIS)--Analog Protocol Version 1, Issue 2", as published in February 1992 by the Information Industry Association in Washington D.C. The AMIS-A protocol provides a method to exchange messages by establishing an exchange session using the public telephone network. Voice message data is sent in analog format during the session. Associated messaging data is sent using conventional dual tone multi frequency ("DTMF") signals.
While digital protocols are known, the use of an analog protocol, including the use of DTMF signals allows for the exchange of messages using conventional voice telephone lines, without requiring digital modem grade lines, not readily available in certain parts of the world.
The existing AMIS-A protocol, however, only supports the most commonly used VM system functions--sending, receiving, and replying to messages. Systems adhering to the AMIS-A protocol are required to provide these minimum functions. The protocol, and the methods implemented using the protocol do not support many VM system functions common to present-day VM systems.
While the AMIS-A protocol does contemplate protocol extensions, neither the nature of the extensions, nor their implementation are defined by the protocol. Moreover, difficulties associated with extending the protocol are not contemplated.